The present invention relates generally to machine tools. More particularly, this invention concerns a grinder system having a grinding head with a unique index/guide assembly for automatically sharpening helical blades in cutting reels of mowing units.
Commercial mowers typically utilize reel type mowing units which must be maintained regularly to assure proper operation. Part of such maintenance involves sharpening the blades and adjusting the bed knives. The sharpening process typically involves two steps: First spin grinding the tips or radial ends of the blades in order to xe2x80x98truexe2x80x99 the rell back to cylindrical shape, and then relief grinding the trailing edge of each blade in order to assure proper contact with the bed knife. This is a manually intensive, time consuming process.
Commercial grinders for this purpose have been available heretofore from Foley United, a division of the assignee hereof, Foley-Belsaw Company, and other manufacturers. However, the grinders of the prior art have typically required numerous and complex adjustments for proper setup, especially in the relief grind mode, depending upon the configuration of the particular mowing unit. Mowing units from different manufacturers have various sizes, number and size of blades, direction of blade twist, etc. As a result, it has been necessary to setup, adjust and then relief grind each blade in the reel of the mowing unit. This is labor intensive and time consuming. Also, it has usually been necessary to first remove the cutting reel from the mowing unit to access the blades for grinding.
More recently, improved grinders have become available. For example, U.S. Pat. No. 5,321,912 to Neary shows a mower reel blade relief grinding device incorporating on a common drive shaft separate slideable grinding wheels, one of which is used in the spin grind mode and the other being used in the relief grind mode. However, this device still requires complicated setup and re-adjustment on a blade-by-blade basis in the relief grind mode.
Heretofore, there has not been available a mower reel grinder which is adapted for automatic indexing so that each of the blades can be relief ground in sequence without further operator attention after initial setup.
The present invention comprises an automatic grinding system which overcomes the foregoing and other difficulties associated with the prior art. In accordance with the invention, there is provided an automatic grinder which is adapted for both spin grinding and relief grinding the blades in a cutting reel without necessarily removing the reel from the mowing unit. The grinder incorporates a grinding head mounted for travel on a carriage along a linear path extending parallel to the rotational axis of the cutting reel in the mowing unit, which is securely clamped in place. The grinding head is also mounted for movement on the carriage between spin and relief grind positions.
An index/guide assembly is mounted for compound movement on the grinding head according to the mode of operation. In the spin grind mode the index/guide assembly is positioned in an inoperative position as the carriage traverses the mowing unit to spin grind the ends of the blades. In the relief grind mode, the index/guide assembly is positioned in an operative position so that associated guide and index fingers can sequentially engage the blades as the carriage traverses the mowing unit to relief grind the trailing edge of each blade, automatically and without further operator attention after inital setup, until all of the blades in the cutting reel have sharpened. Adjustments are provided for adjusting the relief angle as desired.